Sale of Primary Residence and Reside in a Vacation Property in Different State

My wife and I recently retired.  We'll be selling our primary residence in NC and living out of our secondary residence, a condo, in SC.  Are there requirements we must meet to remain in our secondary residence for a length of time to avoid secondary residence taxes when we sell it?  Is there also a benefit to claiming residence in SC and remaining in the state for a specific length of time?